Hi John,
I can't say that I've ever run the control to the end. It is about 15 turns I think, 10 or over for sure. It will be erratic lower down, it probably needs the slip ring cleaned.
I have never seen one of these controls defective mechanically - ever. The shaft shouldn't have axial play, that much I know. The knob does not have a calibration, there is no index mark on it if you've noticed, or the knobs are on the wrong control. The NPN - Off - PNP knob has an index mark, as does the switch for beta - leakage. The beta knob does not have an index mark, there is no calibration. You turn the knob until the meter pointer sits on the "cal" mark ("2"). If you can use the meter, you're good.
Looking at the control again, the shaft appears to be held in place with almost zero play by the three ball bearings in the rear. So if the rear housing was not tight against the front plate, that could do it. The control may be fine otherwise. Someone may have attempted to clean the control.
I can't say that I've ever run the control to the end. It is about 15 turns I think, 10 or over for sure. It will be erratic lower down, it probably needs the slip ring cleaned.
I have never seen one of these controls defective mechanically - ever. The shaft shouldn't have axial play, that much I know. The knob does not have a calibration, there is no index mark on it if you've noticed, or the knobs are on the wrong control. The NPN - Off - PNP knob has an index mark, as does the switch for beta - leakage. The beta knob does not have an index mark, there is no calibration. You turn the knob until the meter pointer sits on the "cal" mark ("2"). If you can use the meter, you're good.
Looking at the control again, the shaft appears to be held in place with almost zero play by the three ball bearings in the rear. So if the rear housing was not tight against the front plate, that could do it. The control may be fine otherwise. Someone may have attempted to clean the control.
OK,,, all good info,,, I will wait for the buyer to decide how to handle it,,, It was over and above to get this for me, and I dont want to compromise his getting a refund,,, Probably not the sellers fault other than it was loose in the shipping box, I doubt he would have sent it with the corrosion crumbs on the meter... I'm surprised teh meter needle still seems to move if I gently move the chassis and returns zeroed...
The PO is horrible with packages...
The PO is horrible with packages...
I'll be honest. If the instrument is in good cosmetic condition, and the meter is in really good condition as you suggest it is, you're ahead of the game. I've bought 4 or 5, two for friends, three for me. My first was new right from Heathkit. The guys working for me destroyed the poor thing. They dropped it several times and it pissed me off they had no respect for my stuff. It finally wore out after being repaired countless times. I then started using a back-up meter I had bought.
Every single meter I bought from the internet has been in new or good condition. They all worked fine and only needed calibrating. The resistor supplied was close tolerance for the time (5% carbon composition), and those also drift terribly. I bought a bunch of 180R, 1% Metal film resistors and calibrated each meter with one that measured close and put that cal resistor inside the instrument for future use. One needed a battery holder, that's it. I do hate the wire and clips, so I use three wire (thinner) AC cord and minigrabber clips. That's the first thing I do when I start to use one. Then I calibrate it after cleaning everything.
I bought an IT-30 (I think) that never showed up. USPS lost it in New York, I'd like one some day just to have in my collection. Otherwise all my meters have been fine.
Every single meter I bought from the internet has been in new or good condition. They all worked fine and only needed calibrating. The resistor supplied was close tolerance for the time (5% carbon composition), and those also drift terribly. I bought a bunch of 180R, 1% Metal film resistors and calibrated each meter with one that measured close and put that cal resistor inside the instrument for future use. One needed a battery holder, that's it. I do hate the wire and clips, so I use three wire (thinner) AC cord and minigrabber clips. That's the first thing I do when I start to use one. Then I calibrate it after cleaning everything.
I bought an IT-30 (I think) that never showed up. USPS lost it in New York, I'd like one some day just to have in my collection. Otherwise all my meters have been fine.
Hi Chris,,,
I'll be honest also!!! I never expected him to buy this in my behalf, let alone give it to me with shipping and he ordered a manual for it which is due today!!! I hope he recovers something out of the transaction,,, But I haven't had luck with online purchases other than Mouser, Digikey etc,,, so I will not deal with them!!!!! There are approx a dozen hamfests/radio shows I can get to every year, and that's where my "treasures" and most parts come from...
I will try to get it working if possible but if I need parts, it will be on the back burner...
Thanks for replying!!!
I'll be honest also!!! I never expected him to buy this in my behalf, let alone give it to me with shipping and he ordered a manual for it which is due today!!! I hope he recovers something out of the transaction,,, But I haven't had luck with online purchases other than Mouser, Digikey etc,,, so I will not deal with them!!!!! There are approx a dozen hamfests/radio shows I can get to every year, and that's where my "treasures" and most parts come from...
I will try to get it working if possible but if I need parts, it will be on the back burner...
Thanks for replying!!!
Hi John,
lol!
You have to have the worst luck of anyone I know! It's common there are minor issues, but hey! That one is over 40 years old.
Remove the control please, take care it doesn't come apart as you take it out in case the tabs are broken. Seat the front part into the control and try the end play on the shaft. It should now be tight I would think. Then rotate it end to end and see if it stops (it probably will). Also look at the tabs, not the end of the world if they are broken clean off. You can solder wire to the side of the pot body, then around the front to solder tight and you should be good. Minor issue, PITA to fix. But, fixable. You end up with a very good meter.
If you get a chance, post some pictures of what you find. It would be easier to disconnect the wires first of course. I'd like to see exactly what you are dealing with, I can only imagine and postulate from what I have seen with different things in the past.
lol!
You have to have the worst luck of anyone I know! It's common there are minor issues, but hey! That one is over 40 years old.
Remove the control please, take care it doesn't come apart as you take it out in case the tabs are broken. Seat the front part into the control and try the end play on the shaft. It should now be tight I would think. Then rotate it end to end and see if it stops (it probably will). Also look at the tabs, not the end of the world if they are broken clean off. You can solder wire to the side of the pot body, then around the front to solder tight and you should be good. Minor issue, PITA to fix. But, fixable. You end up with a very good meter.
If you get a chance, post some pictures of what you find. It would be easier to disconnect the wires first of course. I'd like to see exactly what you are dealing with, I can only imagine and postulate from what I have seen with different things in the past.
Hey,,,
The manual came and is in perfect condition! Previous owner didn't put a mark in it...
Luckiest thing is, I found out I had bad luck early in life,, so I never was a gambler!!! It also taught me that I will have to work for everything I get,,, and never give up... Worked so far!!!
As for the pot, yes I will take it out of teh chassis and the tabs look very well secure... Also, I'm very experienced in working on pots,,, changing resistance wafers, mounting bushings etc,,, I even made a jig that will allow me to drill a hole in dead center of a short 1/4" pot shaft, so I can pin a longer piece of shaft to it,,, I've seen pots with the three balls before, never rebuilt one tho,,, I'd rather use vintage USA pots than the china garbage that is around now!!!!
Also, will give the buyer a chanced to deal with the damage, ebay seller,, etc before I dig into the tester,,,
Pics are a given, I'll post em when I get to dig into it!!!
I still have my tube amps to make me smile!!!!!
The manual came and is in perfect condition! Previous owner didn't put a mark in it...
Luckiest thing is, I found out I had bad luck early in life,, so I never was a gambler!!! It also taught me that I will have to work for everything I get,,, and never give up... Worked so far!!!
As for the pot, yes I will take it out of teh chassis and the tabs look very well secure... Also, I'm very experienced in working on pots,,, changing resistance wafers, mounting bushings etc,,, I even made a jig that will allow me to drill a hole in dead center of a short 1/4" pot shaft, so I can pin a longer piece of shaft to it,,, I've seen pots with the three balls before, never rebuilt one tho,,, I'd rather use vintage USA pots than the china garbage that is around now!!!!
Also, will give the buyer a chanced to deal with the damage, ebay seller,, etc before I dig into the tester,,,
Pics are a given, I'll post em when I get to dig into it!!!
I still have my tube amps to make me smile!!!!!
Hi John,
How many times do I wish I could drill dead centre on a 1/4" shaft! We both know why.
Okay, you are used to working on these things. Fantastic!
The only way I can imagine play there is for the assembly to be spaced apart, or some reason the balls are not in contact with the shaft. I think the shaft is contoured and the balls hold the shaft in. Maybe there is an internal part missing that would take up space internally.
It takes old farts to actually look into fixing a part! lol!
How many times do I wish I could drill dead centre on a 1/4" shaft! We both know why.
Okay, you are used to working on these things. Fantastic!
The only way I can imagine play there is for the assembly to be spaced apart, or some reason the balls are not in contact with the shaft. I think the shaft is contoured and the balls hold the shaft in. Maybe there is an internal part missing that would take up space internally.
It takes old farts to actually look into fixing a part! lol!
I'll dig out my jig and sent ya pic of it,, Its pretty simple... I seem to always confuse you, I'm sorry,, doesn't seem to be any more play in the shaft after pushed it in and it stayed... it tracks nicely after teh low range,,, problem now is teh wafer stops at each end, but teh knob/shaft keeps turning,,, so ya dont know when you reach each end with out seeing the wafer...
Going to read teh book before I dig into it!
Going to read teh book before I dig into it!
lol!
Hi John, no problem at all! Maybe it's me that confuses you?
The shaft stayed in? Cool. That's good news. I think the shaft has more resistance a the ends, but can keep turning. I have never forced any of mine. The shaft rotates the ball bearings and therefore can't have a hard limit. Would that seem right to you?
Yes, read the manual. They explain things well. You'll read about the calibration procedure (simple). I think they are trying to calibrate for 10mA FS, but I should check. A new carbon-zinc battery may have been closer to 1.8 volts back then. I'll have to read it over again as I may be way off base here. If this is the case I'll have to adjust the resistance and procedure. For me it may be more accurate to measure the collector current and set the trimmer that way.
-Chris
Hi John, no problem at all! Maybe it's me that confuses you?
The shaft stayed in? Cool. That's good news. I think the shaft has more resistance a the ends, but can keep turning. I have never forced any of mine. The shaft rotates the ball bearings and therefore can't have a hard limit. Would that seem right to you?
Yes, read the manual. They explain things well. You'll read about the calibration procedure (simple). I think they are trying to calibrate for 10mA FS, but I should check. A new carbon-zinc battery may have been closer to 1.8 volts back then. I'll have to read it over again as I may be way off base here. If this is the case I'll have to adjust the resistance and procedure. For me it may be more accurate to measure the collector current and set the trimmer that way.
-Chris
Shaft doesn't push in and out any more,, but I would think the shaft and knob would stop also,,, The adjustment instructions says "turn pot CCW from rear til it stops" maybe I didn't read it right... I think the balls just make it turn smooth,,, but teh shaft has to stop or it would start over at the beginning end again, as its a circle,,,, I need to understand the manual so I can know how the tester works, then I can probably fix it!!
Hi John,
The shaft can't stop, or the balls. The wiper does stop and that increases turning resistance to the shaft through the ball bearings. I'm not sure if lubrication may make it slip more, certainly the tension will affect that.
Normally you don't need to know as you shouldn't reach the end. You calibrate the test current, and that is not normally at the ends. If the part is shorted or leaky (for shorts you would have checked with your ohmmeter), the leakage measurement will prevent endless turning.
The shaft can't stop, or the balls. The wiper does stop and that increases turning resistance to the shaft through the ball bearings. I'm not sure if lubrication may make it slip more, certainly the tension will affect that.
Normally you don't need to know as you shouldn't reach the end. You calibrate the test current, and that is not normally at the ends. If the part is shorted or leaky (for shorts you would have checked with your ohmmeter), the leakage measurement will prevent endless turning.
OK,, look at page 12 in the manual,,, Adjustments Beta Cal,,Full CCW,,, if teh shaft doesn't finally stop ,how do ya know you are indexed "full"? See teh notch in the back of the pot case, that's usually where some thing inn a pot touched to stop it, I dont want to take this apart without having a replacement in case it goes south tho!!!!
Hi John,
That would stop the actual wiper assembly. It is coupled via friction to the ball bearings and the shaft is coupled via friction to those.
I just tested mine and that is exactly what happens. When you reach the end, the friction increases but the shaft will continue to turn without damaging anything. Maybe someone lubricated the darned thing? Mine may have something like a molykote on it, or some dark grey material. Probably to prevent rust more than anything.
That would stop the actual wiper assembly. It is coupled via friction to the ball bearings and the shaft is coupled via friction to those.
I just tested mine and that is exactly what happens. When you reach the end, the friction increases but the shaft will continue to turn without damaging anything. Maybe someone lubricated the darned thing? Mine may have something like a molykote on it, or some dark grey material. Probably to prevent rust more than anything.
Well friction stop would make sense as its not a screw like one of those little Bourne's pots that are multi turn and come to a stop,,, I used a pair of them to replace the bias pots on the Sui,, However I just tried mine again also, with an ohmmeter on it and it doesn't feel any different in the middle or at either end, no friction''' That's teh bad news,,,, Good news is it tracks pretty good, end to end!!! So the pot actually works, which is good news... I better figure out how this tester works, then I can adjust what needs to be adjusted,,,
Yes.
Also, don't replace bias controls with multi-turn types. Use the same single turn types. You can restrict the range with fixed resistors as some had too much range.
Also, don't replace bias controls with multi-turn types. Use the same single turn types. You can restrict the range with fixed resistors as some had too much range.
The buyer got a partial refund, and said I keep the meter, so I'll dig in tomorrow!!
Well, I replaced bias pots a month or more ago, when the Left side ran away,,, I can pick at my mistakes after the FM/MPX works!!!!
Well, I replaced bias pots a month or more ago, when the Left side ran away,,, I can pick at my mistakes after the FM/MPX works!!!!
I repaired Beta Calibration pot and the open Negative battery holder contact and was able to get thru "Adjustments" Pages 12-13,,, Next is Operation,, Testing-Transistors,,, we'll see how that works out after I understand the procedure!!!!
Looks like this may have turned out well after all,,,, I'm really glad you were able to get a refund, as it did have the problems we pointed out!!!
Quite a nice gift!!!
Thanks again!!!!
Looks like this may have turned out well after all,,,, I'm really glad you were able to get a refund, as it did have the problems we pointed out!!!
Quite a nice gift!!!
Thanks again!!!!
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Hi John,
That's very good news. What was wrong with the beta pot?
The open negative contact also makes sense. What for voltage drop when you're testing though. That's why I replaced mine, it isn't worth the guessing or problems if that causes your instrument to lie to you. The holders are not expensive, and you should get a calibration resistor also.
Sounds like it's good to do nicely. You'll have it forever!
That's very good news. What was wrong with the beta pot?
The open negative contact also makes sense. What for voltage drop when you're testing though. That's why I replaced mine, it isn't worth the guessing or problems if that causes your instrument to lie to you. The holders are not expensive, and you should get a calibration resistor also.
Sounds like it's good to do nicely. You'll have it forever!
Hi Chris,
IDK, PO must have dropped the package,,, as all I did was push the shaft back in til it clicked,, it stays in when tugged so I guess its happy, and tracks good on the ohmmeter,, after the low reading jitters!!! I put a copper connection rivet to contact the battery,, gotta be as good as it was...
Yep, it had a 180R carbon comp in the case, but it was out of value... I went thru some I had and measured one 180R,, its a 5%,,,, but proof of concept!!
IDK, PO must have dropped the package,,, as all I did was push the shaft back in til it clicked,, it stays in when tugged so I guess its happy, and tracks good on the ohmmeter,, after the low reading jitters!!! I put a copper connection rivet to contact the battery,, gotta be as good as it was...
Yep, it had a 180R carbon comp in the case, but it was out of value... I went thru some I had and measured one 180R,, its a 5%,,,, but proof of concept!!
